I have been using DVRack for over 2 years, and it is a great tool.
There is a new patch available to solve the over 1 hr clip length problem – before the patch i would hit the record button every 50 minutes or so and it would give me a new clip without missing a frame.
The only other problem i have is with my seagate external drives – if the drive is over 200 gig, the drive goes to sleep – just need to wait 5-10 secs after you hit record to come up. As for the laptop, make sure you have all the power management turned off – this can slow down the displays on the dvrack.